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Original question:

INA228-Q1: Ask the difference between INA228 &I INA233

INA228: Over current monitoring

Carlo
Expert 7715 points
Part Number: INA228
Other Parts Discussed in Thread: INA233

Hi team,

Our customer is using the INA233 to monitor overcurrent and send an alert to the system whenever it occurs. Since there is no stock available, they're considering the INA228. It seems that this chip does monitoring for over/under voltage, over/under power, and over temperature limits. If they want to continue monitoring of overcurrent, is it possible to just set the INA228 to alert on overpower given that they will have a stable and constant voltage from the power supply? Can they just set the Power Limit Pmax = V * Imax, where V is the constant shunt voltage and Imax is the desired "overcurrent" limit? If so, are equations 3 & 5 from page 31 be used to calculate the triggered Imax value as: Imax = V/Power Register value?

Thank you in advance for the clarifications.

Regards,
Carlo

  • 0
    TI__Expert 4720 points

    Hello Carlo,

    Actually the INA228 will monitor over/under current. You will need to configure the shunt voltage over/under registers. This is because the current is derived from the shunt voltage ie I = Vshunt/Rshunt. By using a known Rshunt you can calculate the correct Vshunt value that will cause an Imax over limit alert. Vshunt_max = Imax*Rshunt. 

    So power is calculated based on the current and BUS voltage. So your method would not work. Your method could work if you used the bus voltage instead but you must understand that if the bus voltage changes you might alert to an over current when the voltage has gone up but not the current. While if the bus voltage goes down and the current goes up you might not get an over current alert when you would expect it. 

    If you have any questions please reply

    Regards,

    Castrense